気候：温暖化のために上陸後のハリケーンが衰弱が遅くなる

North Atlantic hurricanes are weakening more slowly as they hit land than in the past as a result of rising sea temperatures suggests a paper in Nature. The findings indicate that the destructive impact from hurricanes could increase further inland in the future.

Hurricanes are powered by moisture from the sea and, therefore, decay rapidly and lose strength following landfall, limiting damage to coastal areas. Although climate warming is thought to have an effect on hurricane intensity, the impact on hurricane decay is not well understood.

Lin Li and Pinaki Chakraborty analyse data from landfalling North Atlantic hurricanes from 1967 to 2018. They found that the extent of hurricane decay has declined in line with a corresponding rise in sea temperatures. Using computer simulations the authors indicate that warmer sea temperatures enable hurricanes to hold more moisture when they make landfall, which slows their decay. The authors report that hurricanes in 1960 were likely to decay by 75 per cent within a day of landfall, whereas for present-day hurricanes the decay is 50 per cent.

The authors note that as global temperatures increase, inland areas are likely to be more affected. These areas may also be less prepared than coastal regions for hurricanes, with direct implications for hazard preparation. Further research is needed to understand the implications on hurricanes from other ocean basins.